Starting System Circuit Description. Chevrolet PJJ 2000

For 1990-2009 cars

When the Ignition Switch is moved to START, the battery voltage is applied to the Starter Solenoid. Both Solenoid Windings are energized. The circuit through the Pull In Winding is completed to ground through the Starter Motor. The Windings work together magnetically to pull in and hold the Plunger. The Plunger moves the Shift Lever. This action causes the Drive Assembly to rotate as it engages with the Flywheel ring gear on the engine. At the same time, the Plunger also closes the solenoid switch contacts in the Starter Solenoid. Full battery voltage is applied directly to the Starter Motor and it cranks the engine.

As soon as the solenoid contacts close, voltage is no longer applied through the Pull in Winding, since battery voltage is applied to both ends of the Windings. The Hold In Winding remains energized, and its magnetic field is strong enough to hold the Plunger, Shift Lever, and Drive Assembly Solenoid switch contacts in place to continue cranking the engine.

When the ignition switch is released from the START position, battery voltage is removed from the Starter Solenoid and the junction of the two Windings. Voltage is applied from the motor contacts through both Windings to ground at the end of the Hold in Winding. However, the voltage applied to the Pull in Winding is now opposing the voltage applied when the Winding was first energized. The magnetic fields of the Pull in and Hold in Windings now oppose one another. The Return Spring then causes the Drive Assembly to disengage and the solenoid switch contacts to open simultaneously. As soon as the contacts open, the starter circuit is turned OFF.